The overall goal of this work is to improve outcomes for people who use single-switch scanning. Single-switch scanning is used by individuals with severe motor and communicative disabilities as a method for entering text and data into computers and augmentative communication devices. The text entry rate (TER) with single-switch scanning can be less than one word per minute, but altering timing parameters and scanning matrix configurations can dramatically affect communication rate [1, 2, 21]. The challenge is identifying the most appropriate configuration based on the needs of each individual user and the configuration options presented by each scanning system. We propose to develop software that allows clinicians and consumers to identify the most appropriate configuration for a scanning system. The software will help clinicians to choose the right configuration options and configure those options to maximize TER. The software will also help consumers adapt their configuration over time as their needs and abilities change. In Phase I we will complete the following tasks: 1. Develop a prototype software program to determine scanning system parameter settings that will increase TER by two-fold or more. 2. Validate the software with current users of single-switch scanning. 3. Conduct a focus group with clinicians to gather feedback on system requirements, user interface, and utility. To be successful, we must show that our tool will arrive at scanning system settings that will increase TER for subjects by two-fold or more. We must also show that the simulation model within our software predicts TER to within a 10% error or less, across a variety of scanning configurations. This forms the foundation for Phase II by verifying both the technical feasibility of performing model simulations and the clinical impact of using the model to significantly enhance users'text entry rate. PUBLIC HEALTH RELEVANCE: The proposed software promises to provide real benefits to people who use single- switch scanning systems by configuring the system to the user's needs. An improved system configuration can make a real difference in an individual's productivity and ability to communicate. The software will also benefit clinicians by providing them with a tool that makes it easier and more effective to perform the complex task of configuring a single-switch scanning system. This tool will help them provide better services to their clients.